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Characteristics of three new avian sarcoma viruses, ASV 9, ASV 17, and ASV 25
Abstract:
Three new avian sarcoma viruses, ASV 9, ASV 17, and ASV 25, were isolated from spontaneous tumors. They transform chicken embryo fibroblasts but not hemopoietic cells and induce fibrosarcomas in young chicks. All three viruses belong to the envelope subgroup A and cannot replicate without a helper virus, because they lack the pol and most, if not all, of the env gene. ASV 9 and ASV 17 have a genome of 5.0 kb; the genome of ASV 25 is 6.0 kb. The following onc sequences were tested for homology to the genomes of the three new avian sarcoma viruses: src, fps, yes, myc, myb, erbA, and erbB. These tests were negative except for erbB which showed faint hybridization with the genome of ASV 25. ASV 9 codes for a prominent 130-kdalton gag-linked transformation-specific protein. ASV 17 and ASV 25 transformed cells appear to contain multiple gag-linked transformation-specific proteins that still require further study.
Insights
Three novel avian sarcoma viruses (ASVs) were isolated from tumors. These ASVs transform specific cells and induce fibrosarcomas in chicks, with ASV 25 showing a link to the erbB oncogene.
Area of Science:
- Virology
- Oncology
- Molecular Biology
Background:
- Spontaneous tumors in chickens can harbor novel oncogenic viruses.
- Avian sarcoma viruses (ASVs) are retroviruses known to cause tumors in birds.
- Understanding the genetic makeup and oncogenic potential of new ASV isolates is crucial for cancer research.
Purpose of the Study:
- To isolate and characterize three new avian sarcoma viruses (ASVs) from spontaneous tumors.
- To determine the transforming capabilities and oncogenic potential of these novel ASVs.
- To investigate the genetic relationship of these ASVs to known oncogenes.
Main Methods:
- Isolation of viruses from spontaneous avian tumors.
- Cell transformation assays using chicken embryo fibroblasts and hemopoietic cells.
- Viral genome analysis, including size determination and Southern hybridization with oncogene probes.
- Analysis of viral protein products using SDS-PAGE.
Main Results:
- Three new ASVs (ASV 9, ASV 17, ASV 25) were isolated and characterized.
- These viruses transform chicken embryo fibroblasts but not hemopoietic cells, inducing fibrosarcomas in chicks.
- ASVs 9 and 17 possess a 5.0 kb genome, while ASV 25 has a 6.0 kb genome.
- ASV 25 showed faint hybridization with the erbB oncogene; ASV 9 encodes a 130-kDa gag-linked protein, and ASVs 17/25 have multiple such proteins.
Conclusions:
- The newly isolated ASVs represent distinct viral entities with specific transforming properties.
- The genetic analysis suggests a potential link between ASV 25 and the erbB oncogene.
- Further studies are needed to fully elucidate the transformation mechanisms mediated by the gag-linked proteins in ASV 17 and ASV 25.